Lecture 3

Question 1

Why do we need virtual memory?

Answer 1

Programs can be large. With rams limit, only a few programs would completely fit in it, limiting the amount of multiprocessing that can be done. 80:20 Rule 80% of the code is used 20% of the time. You don’t need the entire program to be in the memory. Virtual Memory allows the operating system to have multiple processes in the Ram, whose total memory usage would normally exceed the physical limit.

Question 2

How does virtual memory work?

Answer 2

Each process is allocated its own address space known as virtual address space.

Question 3

How much memory does each virtual address space have?

Answer 3

4kB

Question 4

What is the name of physical memory blocks?

Answer 4

Frames